2161868556 has 12 divisors (see below), whose sum is σ = 5044359992. Its totient is φ = 720622848.

The previous prime is 2161868551. The next prime is 2161868557. The reversal of 2161868556 is 6558681612.

2161868556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (2161868551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90077845 + ... + 90077868.

Almost surely, 2^2161868556 is an apocalyptic number.

It is an amenable number.

2161868556 is an abundant number, since it is smaller than the sum of its proper divisors (2882491436).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2161868556 is a wasteful number, since it uses less digits than its factorization.

2161868556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180155720 (or 180155718 counting only the distinct ones).

The product of its digits is 691200, while the sum is 48.

The square root of 2161868556 is about 46495.8982707077. The cubic root of 2161868556 is about 1293.0334549070.

The spelling of 2161868556 in words is "two billion, one hundred sixty-one million, eight hundred sixty-eight thousand, five hundred fifty-six".